This year, major emphasis has been placed upon the development of new therapy for patients with hereditary angioedema. A drug was sought which would be relatively non-toxic, which could be given to both men and women and which would control symptoms of the disease. For a number of reasons, a drug named Danazol produced by Sterling Winthrop Laboratories was chosen for study. A double blind study was completed of the use of this drug in both men and women. The drug was shown to be highly effective in the treatment of hereditary angioedema. Of equal interest is the fact that the drug was shown to correct the genetically controlled biochemical abnormality, returning C1 esterase inhibitor and C4 levels to normal in most patients on therapy. It would appear that this drug will be the most useful available method for the treatment of this disease. A second project was begun during this period concerning the use of purified proparations of the C1 esterase inhibitor prepared by the American Red Cross for infusion therapy of patients with hereditary angioedema during acute attacks. These studies are only starting at the present time, and it is not yet known whether this will be effective therapy or not.